JEE Questions for Physics Wave Optics Quiz 3 - MCQExams.com

In Young’s double slit experiment, distance between tow sources is 0.1 mm. The distance of screen form the sources is 20 cm.Wavelength of light used is 5460 Å Then angular position of first dark fringe is A.
  • 0.08o
  • 0.16o
  • 0.20o
  • 0.32o
In the ideal double slit experiment, when a glass plate of refractive index 1.5 and thickness t is introduced in the path of one of the interfering beams of wavelength λ, the intensity at the position of central max. remains unchanged . Minimum thickness of glass plate is
  • 2 λ
  • 2 λ/3
  • λ/3
  • λλ
An astronaut is looking down on earth’s surface from a space shuttle at an altitude of 500 km. Assuming that the astronaut’s pupils’ diameter 5 mm and the wavelength of visible light is 500 nm, the astronaut will be able to resolve linear objects of the size of about
  • 0.5 m
  • 5 m
  • 50 m
  • 500m
When an unpolarized light of intensity I0 is incident on a polarizing sheet, the intensity of the light which does not get transmitted is
  • I0
  • zero

  • Physics-Wave Optics-95325.png

  • Physics-Wave Optics-95326.png
In Young’s double slit experiment, intensity at a point is (1/of the maximum intensity Angular position of this point is
  • sin-1 (λ/d)
  • sin-1 (λ/2d)
  • sin-1 (λ/3d)
  • sin-1 (λ/4d)
A beam of electron is used in a YDSE experiment. The slit width is d .When the velocity of electron is increased,then
  • no interference is observed
  • fringe width increases
  • fringe width decreases
  • fringe width remains same
In case of linearly polarised light, the magnitude of electric field vector
  • does not change with time
  • varies periodically with time
  • increases and decreases linearly with time
  • is parallel to the direction of propagation
When the angle of incidence on a material is 60o, the reflected light is completely polarized. The velocity of the refracted ray inside the material in m/s is
  • 3 × 108
  • 2)
    Physics-Wave Optics-95329.png

  • Physics-Wave Optics-95330.png
  • 0.5 × 108
A glass slab of thickness 8 cm contains the same number of waves as 10 cm of water when both are traversed by the same monochromatic light. If the refractive index of water is 4/3, the refractive index of glass is
  • 5/4
  • 3/2
  • 5/3
  • 16/15
When an unpolarised light of intensity I0 is incident on a polarising sheet, the intensity of the light which does not get transmitted is

  • Physics-Wave Optics-95333.png
  • 2)
    Physics-Wave Optics-95334.png
  • zero
  • I0
Two coherent point sources S1 and S2 are separated by a small distance d as shown in the figure. The fringes obtained on the screen will be
Physics-Wave Optics-95335.png
  • points
  • straight lines
  • semi-circle
  • concentric circles
A fringe width of a certain interference pattern is 13 = 0.002 cm. What is the distance of 5th dark fringe from centre?
  • 9 × 10-3 cm
  • 11 × 10-2 cm
  • 1.1 × 10-2 cm
  • 3.28 × 10-6 cm
A light source, which emits two wavelengths λ1 = 400 nm and λ2 = 600 am, is used Young's double slit experiment. If recorded fringe widths for λ1 and λ2 are β1 and β2 and the number of fringes for them within a distance y on one side of the central maximum are m1 and m2 respectively, then
  • β2 > β1
  • m1 > m2
  • from the central maximum, 3rd maximum of λ2 overlaps with 5th minimum of λ1.
  • the angular separation of fringes of λ1 is greater than λ2.
In a Young's double slit experiment, the slit separation is 1 mm and the screen is lm from the slit. For a monochromatic light of wavelength 500 nm, the distance of 3rd minima from the central maxima is
  • 0.50 mm
  • 1.25 mm
  • 1.50 mm
  • 1.75 mm
Consider the following statements in case of Young's double slit experiment.
I. A slit S is necessary, if we use an ordinary extended source of light.
II. A slit S is not needed, if we use an ordinary but well collimated beam of light.
III. A slit S is not needed, if we use a specially coherent source of light.
Which of the above statements are correct?
  • I and III
  • II and III
  • I and II
  • I, II and III
In Young's double slit experiment the two slits are d distance apart. Interference pattern is observed on a screen at a distance D from the slits. A dark fringe is observed on the screen directly opposite to one of the slits. The wavelength of light is

  • Physics-Wave Optics-95337.png
  • 2)
    Physics-Wave Optics-95338.png

  • Physics-Wave Optics-95339.png

  • Physics-Wave Optics-95340.png
Young's double slit experiment is carried out by using green, red and blue light, one colour at time. The fringe widths recorded are βG , βR and βB respectively. Then,
  • βG > βR > βB
  • βB > βG > βR
  • βR > βB > βG
  • βR > βG > βB
In Young's double slit experiment, fringes of width (3 are produced on a screen kept at a distance of 1 m from the slit. When the screen is moved away by 5 × 10-2 m, fringe width changes by 3 × 10-5 m. The separation between the slits is 1 ×10-3 m. The wavelength of the light used is ... nm.
  • 400
  • 500
  • 600
  • 700

Physics-Wave Optics-95341.png
  • 3 : 2
  • 2 : 1
  • √2 : 1
  • 4 : 1

Physics-Wave Optics-95343.png
  • 4
  • 2
  • 1
  • 0.5
In an interference experiment, phase difference for points where the intensity is minimum is (n =1, 2, 3, ... )
  • nπ
  • (n + 1)π
  • (2n – 1)π
  • zero

Physics-Wave Optics-95344.png
  • 0.866
  • 0.707
  • 0.807
  • 0.75
A mixture of light, consisting of wavelength 590 nm and an unknown wavelength, illuminates Young's double slit and gives rise to two overlapping interference patterns on the screen. The central maximum of both lights coincide. Further, it is observed that the third bright fringe of known light coincides with the 4th bright fringe of the unknown light. From this data, the wavelength of the unknown light is
  • 393.4 nm
  • 885.0 nm
  • 442.5 nm
  • 776.8 nm
A slit of width α is illuminated with a monochromatic light of wavelength λ from a distant source and the diffraction pattern is observed on a screen placed at a distance D from the slit. To increase the width of the central maximum, one should
  • decrease D
  • decrease α
  • decrease λ
  • the width cannot be changed
In a double slit experiment, the screen is placed at a distance of 1.25 m from the slits. When the apparatus is immersed in water (μw = 4/3), the angular width of a fringe is found to be 0.2°.When the experiment is performed in air with same set up, the angular width of the fringe is
  • 0.4°
  • 0.27°
  • 0.35°
  • 0.15°
  • 0.22°
In Young's experiment, the third bright band for light of wavelength 6000A° coincides with the fourth bright band for another source of light in the same arrangement. Then, the wavelength of second source is
  • 3600°
  • 4000°
  • 5000A°
  • 4500A°
  • 5500A°
In Young's double slit experiment, distance between two slits is 0.28 mm and distance between slits and screen is 1.4 m. Distance between central bright fringe and third bright fringe is 0.9 cm, what is the wavelength of light used ?
  • 4000 A°
  • 6000 A°
  • 3000 A°
  • 5000 A°
The Young's double slit experiment is performed with blue and with green lights of wavelengths 4360 A° and 5460 A° respectively. If x is the distance of 4th maximum from the central one, then
  • x (blue) = x (green)
  • x (blue) > x (green)
  • x (blue)

  • Physics-Wave Optics-95348.png
Two light sources are said to be of coherent nature
  • when they have same frequency and a varying phase difference
  • when they have same frequency and a constant phase difference
  • when they have constant phase difference and different frequencies
  • when they have varying phase difference and different frequencies
In Young's double slit interference pattern the fringe width
  • can be changed only by changing the wavelength of incident light
  • can be changed only by changing the separation between the two slits
  • can be changed either by changing the wavelength or by changing the separation between two sources
  • is a universal constant and hence, cannot be changed
In a Young's experiment, two coherent sources are placed 0.90 mm apart and the fringes are observed lm away. If it produces the second dark fringe at a distance of 1 mm from the central fringe, the wavelength of monochromatic light used would be
  • 60 × 10-4 cm
  • 10 × 10-4 cm
  • 10 × 10-5 cm
  • 6 × 10-5 cm
In Young's double slit experiment, the interference pattern is found to have an intensity ratio between bright and dark fringes is 9, this implies that
  • the intensities at the screen due to two slits are 5 units and 4 units respectively
  • the intensities at the screen due to the two slits are 4 units and 1 units, respectively
  • the amplitude ratio is 7
  • the amplitude ratio is 6
Light from two coherent sources of the same amplitude A and wavelength λ, illuminates the screen. The intensity of the central maximum is I0. If the sources were incoherent, the intensity at the same point will be
  • 4I0
  • 2I0
  • I0
  • I0/2
In Young's double slit experiment with sodium vapour lamp of wavelength 589 run and the slits 0.589 mm apart, the half angular width of the central maximum is

  • Physics-Wave Optics-95351.png
  • 2)
    Physics-Wave Optics-95352.png

  • Physics-Wave Optics-95353.png

  • Physics-Wave Optics-95354.png
A slit of width a is illuminated by red light of wavelength 6500 Å. If the first minimum falls at θ = 30°, the value of a is
  • 6.5 × 10-4 mm
  • 1.3 micron
  • 3250 A°
  • 2.6 × 10-4 cm
  • 1.3 × 10-4 m

Physics-Wave Optics-95357.png
  • 5/3
  • 4
  • 81/625
  • 16
  • 1/2
In the Young's double slit experiment, the central maxima is observed to be I0. If one of the slits is covered, then the intensity at the central maxima will become

  • Physics-Wave Optics-95358.png
  • 2)
    Physics-Wave Optics-95359.png

  • Physics-Wave Optics-95360.png

  • Physics-Wave Optics-95361.png
If fringes width λ = 5.89 × 10 -5 CM is 0.431 mm and shift of white central fringe on introducing a mica sheet in one path is 1.89 mm. Thickness of the mica sheet will be μ =1.
  • 4.38 × 10 -6 m
  • 5.38 × 10 -6 m
  • 6.38 × 10 -6 m
  • None of these
In Young's double slit experiment, a minima is observed when path difference between the interfering beam is
  • λ
  • 1.5 λ
  • 2 λ
  • 2.5 λ
In Young's experiment, using red light (λ = 6600A°), 60 fringes are seen in the field of view. How many fringes will be seen by using violet light (λ = 4400A°) ?
  • 10
  • 20
  • 45
  • 90
  • 35
The width of a single slit if the first minimum is observed at an angle 2° with a light of wavelength 6980 Å
  • 0.2 mm
  • 2 × 10-5 mm
  • 2 × 105 mm
  • 2 mm
  • 0.02 mm
In a Young's double slit experiment, the separation between the two slits is 0.9 mm and the fringes are observed 1 m away. If it produces the second dark fringe at a distance of 1 mm from the central fringe, the wavelength of the monochromatic source of light used is
  • 450 mm
  • 400 mm
  • 500 mm
  • 600 mm
In double slit experiment, the distance between two slits is 0.6 mm and these are illuminated with light of wavelength 4800Å. The angular width of first dark fringe on the screen distant 120 cm from slits will be
  • 8 × 10-4 rad
  • 6 × 10-4 rad
  • 4 × 10-4 rad
  • 16 × 10-4 rad
In Young's double slit experiment, the slits are 3 mm apart. The wavelength of light used is 5000 A° and the distance between the slits and the screen is 90 cm. The fringe width in (mm) is
  • 1.5
  • 0.015
  • 2.0
  • 0.15
In Young's double slit experiment intensity at a point is (1/of the maximum intensity. Angular position of this point is
  • sin (-1 (λ/d)
  • sin (-1 (λ/2d)
  • sin (-1 (λ/3d)
  • sin (-1 (λ/4d)
The angular size of the central maxima due to a single slit diffraction is (a → slit width)

  • Physics-Wave Optics-95366.png
  • 2)
    Physics-Wave Optics-95367.png

  • Physics-Wave Optics-95368.png

  • Physics-Wave Optics-95369.png
Two stars are situated at a distance of 8 light year from the earth. These are to be just resolved by a telescope of diameter 0.25 m. If the wavelength of light used is 5000 Å, then the distance between the stars must be
  • 3 × 1010 m
  • 3.35 × 1011 m
  • 1.95 × 1011 m
  • 4.32 × 1010 m
The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 Å is of the order of
  • 106 rad
  • 10-2 rad
  • 10-4 rad
  • 10-6 rad
A parallel beam of light of wavelength 6000 Å gets diffracted by a single slit of width 0.3 mm. The angular position of the first minima of diffracted light is
  • 6 × 10-3 rad
  • 1.8 × 10-3 rad
  • 3 × 10-3 rad
  • 2 × 10-3 rad
Consider Fraunhofer diffraction pattern obtained with a single slit at normal incidence. At the angular position of first diffraction minimum, the phase difference between the wavelets from the opposite edges of the slit is

  • Physics-Wave Optics-95373.png
  • 2)
    Physics-Wave Optics-95374.png
  • π
  • 2π
0:0:1


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